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  <title>取得指定的颜色加透明度的索引值</title>

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</div><hr /><div id="function.imagecolorexactalpha" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">imagecolorexactalpha</h1>
  <p class="verinfo">(PHP 4 &gt;= 4.0.6, PHP 5)</p><p class="refpurpose"><span class="refname">imagecolorexactalpha</span> &mdash; <span class="dc-title">取得指定的颜色加透明度的索引值</span></p>

 </div>
 <div class="refsect1 description" id="refsect1-function.imagecolorexactalpha-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="type">int</span> <span class="methodname"><strong>imagecolorexactalpha</strong></span>
    ( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$image</code></span>
   , <span class="methodparam"><span class="type">int</span> <code class="parameter">$red</code></span>
   , <span class="methodparam"><span class="type">int</span> <code class="parameter">$green</code></span>
   , <span class="methodparam"><span class="type">int</span> <code class="parameter">$blue</code></span>
   , <span class="methodparam"><span class="type">int</span> <code class="parameter">$alpha</code></span>
   )</div>

  <p class="para rdfs-comment">
   返回图像调色板中指定颜色加透明度的索引值。
  </p>
 </div>

 <div class="refsect1 parameters" id="refsect1-function.imagecolorexactalpha-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>

    <dt>
<em><code class="parameter">image</code></em></dt>

<dd>
<p class="para">由图象创建函数(例如<span class="function"><a href="function.imagecreatetruecolor.html" class="function">imagecreatetruecolor()</a></span>)返回的图象资源。</p></dd>

    
     <dt>
<em><code class="parameter">red</code></em></dt>

     <dd>

      <p class="para">红色成分的值。</p>
     </dd>

    
    
     <dt>
<em><code class="parameter">green</code></em></dt>

     <dd>

      <p class="para">绿色成分的值。</p>
     </dd>

    
    
     <dt>
<em><code class="parameter">blue</code></em></dt>

     <dd>

      <p class="para">蓝色成分的值。</p>
     </dd>

    
    
     <dt>
<em><code class="parameter">alpha</code></em></dt>

     <dd>

      <p class="para">
       A value between <em>0</em> and <em>127</em>.
       <em>0</em> indicates completely opaque while 
       <em>127</em> indicates completely transparent.
      </p>
     </dd>

    
   </dl>

   The colors parameters are integers between 0 and 255 or hexadecimals
   between 0x00 and 0xFF.
  </p>
 </div>

 <div class="refsect1 returnvalues" id="refsect1-function.imagecolorexactalpha-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   返回图像调色板中指定颜色加透明度的索引值。
   如果颜色不在图像的调色板中，返回 -1。
  </p>
 </div>

 <div class="refsect1 examples" id="refsect1-function.imagecolorexactalpha-examples">
  <h3 class="title">范例</h3>
  <div class="example" id="example-3128">
   <p><strong>Example #1 Get colors from the GD logo</strong></p>
   <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /><br /></span><span style="color: #FF8000">//&nbsp;Setup&nbsp;an&nbsp;image<br /></span><span style="color: #0000BB">$im&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">imagecreatefrompng</span><span style="color: #007700">(</span><span style="color: #DD0000">'./gdlogo.png'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$colors&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">=&nbsp;Array();<br /></span><span style="color: #0000BB">$colors</span><span style="color: #007700">[]&nbsp;=&nbsp;</span><span style="color: #0000BB">imagecolorexactalpha</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">255</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$colors</span><span style="color: #007700">[]&nbsp;=&nbsp;</span><span style="color: #0000BB">imagecolorexactalpha</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">127</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$colors</span><span style="color: #007700">[]&nbsp;=&nbsp;</span><span style="color: #0000BB">imagecolorexactalpha</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">255</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">255</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">255</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">55</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$colors</span><span style="color: #007700">[]&nbsp;=&nbsp;</span><span style="color: #0000BB">imagecolorexactalpha</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">100</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">255</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">52</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">20</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">print_r</span><span style="color: #007700">(</span><span style="color: #0000BB">$colors</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">//&nbsp;Free&nbsp;from&nbsp;memory<br /></span><span style="color: #0000BB">imagedestroy</span><span style="color: #007700">(</span><span style="color: #0000BB">$im</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
   </div>

   <div class="example-contents"><p>以上例程的输出类似于：</p></div>
   <div class="example-contents screen">
<div class="cdata"><pre>
Array
(
    [0] =&gt; 16711680
    [1] =&gt; 2130706432
    [2] =&gt; 939524095
    [3] =&gt; 342163252
)
</pre></div>
   </div>
  </div>
 </div>

 <div class="refsect1 notes" id="refsect1-function.imagecolorexactalpha-notes">
  <h3 class="title">注释</h3>
  <blockquote class="note"><p><strong class="note">Note</strong>: <span class="simpara">此函数需要 GD 2.0.1 或更高版本(推荐 2.0.28 及更高版本)。</span></p></blockquote>
 </div>

 <div class="refsect1 seealso" id="refsect1-function.imagecolorexactalpha-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="function"><a href="function.imagecolorclosestalpha.html" class="function" rel="rdfs-seeAlso">imagecolorclosestalpha()</a> - 取得与指定的颜色加透明度最接近的颜色</span></li>
   </ul>
  </p>
 </div>

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